Coring apparatus



Oct. 28, 1941. J. E. HOFFOSS CORING APPARATUS Filed Nov. 23, 1940 A%IZ J /I/n E. f/offoss INVENTOR.

- ATTO Patented Oct. 19 41 I x or a latchingmeans for COBiNG mane'ros John E; Hofloss, Houston, Tex, assignor to Road Houston, Ten, 1!. corpora- Roller Bit Comp tiono! Texas Application November 2 the so-called for its general object the provision latching; a wire line paratus of type end-has description taken in companying drawing in which is set forth by way of illustration one embodiment of this invention;

In the drawing: Fig. 1 shows alongitudinal cross section through the lower portion of a. well and drill stem in which is located and shown inelevation a core barrel with a view in cross section of shown in Fig. 1.

to Fig. 2 but showin Fig. 2 is an enlarged the latching mechanism Fig. 3 is a view similar the latching meohanism in active position as it would be in use during the taking of a core.

The drill stem, be of any conventional shown consisting of a fishtail bit- I which is secured to the lower end of a drill collar 2 and that in turn is carried by a sub 3 on the lower end of the drill pipe}. The bit I is of the type adapted to permit the lower end of the core barrel to project or protrude below the'bit and and bit in this instance may latch thereon constructedv vin accordance with this invention.

design, the one here core cutter connection with the'aca, 1940, serial no. 366.8139

comma (01. 255 -12) I This invention relates to a core taking apwire line core barrel 7 head having cuttingteeth e, adapted to form the core, This core barrel is carried on the lower end of the carrier body 'l by means oi a telescoping connection core barrel or other tool in operative position normally urged to its lowermost position by in a corebit duringthe operation thereof. means or a spring 9 incorporated in the tele- In the ..con ventional type of wire line. core scoping section.

barrel latching apparatus, there is a latching dog I lghe carrier body I' is slotted adjacent its upor bolt which is constantly urged outwardly in per end and receives the latching dog "which a lateral direction with respect to the axis of 10 ispivoted in said slotat H adjacent the lower the core barrel bymeans or spring, or some end of the dog. The upper. end or the dog i other element which will perform the same func- 7 provided with a. slot 12 in which is slidably -.tion. With such an apparatus, while the core mounted a'pin l3 carriedon the plunger I 4 barrel is being moved downwardly through the that extends upwardly through the upper end drill stem and into the. well, the latching bolt v of the carrier body and is slidably mounted will be constantly dragging against the'wall therein. The upper end or this plu er H is or the pipe or striking on the shoulders of the provided witha spearhead I! and surrounding tool joints which make up a -drill stem. This, theplunger above the carrier body-1 is a spring of course, is injurious to the latching dog itself, 18 which normally holds the plunger in its, upas well as to the pipe and drill stem and is an 20 permofl position. Surrounding the plunger l4 undesirable feature. v a a short distance below itsupper end is an en- It is an object or this invention, thereiore, to 'I rgemen't- 'II for a purpose presently to be provide a latching mechanism for holding a core described. i f barrel-ot'the type set forth; which latching v The sub lis internally threaded at I! within mechanism ,will ordinarily be in inactive po iits lower-end to receive the sleeve la which is tion and'which will. 'thereiore, be capable or adapted to receive the latching dog It for the passing downwardly through the drill stem withpurpose of latching the core barrel in operative out striking against the parts thereof. position and preventingits rotation with respect Other objects and advantages or this invento the drill stem. :The sleeve 19 has at its upper tion will become apparent from the following end a zone 20 of restricted cross section, the same being of such size that it will barely permit thepassage or the enlarged part I! on the plunger 85 seats in proper positidniwithin the drill bit, the

to cut the core from the formation in advance ot'the major cutting portion of the bit. For this purpose the core barrel 5 is formed with a enlargement i'l will occupy restricted zone I. of theg'sleeve [0. Then, when the pumping of slush and slush is forced downwardly through the drill stein prior to and during the normal operation of the bit in taking the core, this slush will move the enlarged member l'l downwardly spring Ii until; the the zone 20 so that the passage of slush can take place. This downwardmovement of the plunger ll causes the lateral movement of the latching dog I. so that it will engage within the driving slot 2!, which is formed in the lower end of the sleeve ii. The latching mechanism will thus be held in active position during the entire operation or the apparatus in taking a core. However, as I 8. v The core barrel is a position within the against the tension of the enlarged member I1 is below seated in sa tool, a latching member mounted on said carrier head l5 may then be engaged by the usual ove shot and the core barrel assembly removed. In the event the spring l6 should fail to move the plunger M upwardly when theflow oi the slush ceases, the pull of the overshot on the spearhead l5 will serve this purpose.

It will be appreciated that while the device illustrated and described is a core barrel, this invention is applicable as well to various other tools, such as center bits for example, which are adapted to be passed down and retrieved through a drill stem.

It will be seen from theioregoing that a means has been provided for carrying out all of the objects and advantages sought by this invention.

Having described my invention, I claim:

1. In a" latching mechanism for a wire line core barrel or the like, a carrier body adapted to be connected to the upper end of such core barrel, a latching member mounted on said carrier body for lateral movement with respect thereto into projected latching position, a pl nger on saidcarrier body above said latching ember and having an engagementwith said latching member whereby upon upward movement of said plunger said latching member will be retracted and upon downward movement of said plunger said latching member will be projected, spring means for holding said plunger normally in its uppermost position with said latching member retracted, and an enlargement on said plunger adapted to be acted upon by the flow of slush downwardly past said plunger to move said plunger downwardly and to move said latching member into latching 1' a position. 2. In combination, a drill stem, a core bit on the lower end of said drill stem having an open-- ing therein adapted to receive the lower end of a core barrel, said drill stem having a restricted f part therein above said core bit, a tool adapted to be passed downwardly through said drill stem and idcore bit, a carrier body on said ward movement of said member member will be projected,

normally holding said plunger-in its uppermost body for lateral movement with respect thereto into and out o! latching position with respect to .said drill stem, 9. plunger on said carrier body moveable upwardly and downwardly and connected with said latching member whereby upon upward movement of said plunger said latching member will be restrictedand whereby on downsaid latching resilient means for position with respect to said latching member, and an enlargement on said plunger adapted to be normally positioned within said restricted portion of the drill stem when said tool is seated within the core bit and said plunger is in its uppermost position whereby a flow of slush downwardly-through said drill stem will act upon said enlargement on the plunger andcause downward movement of the plunger to latch said tool in place.

3. In combination, a core drilling assembly having a passage therethrough with a zone of reduced diameter therein and a keeper adapted to receive a latch, a tool adapted to be passed downwardly through said passage and including a carrier body, a latching member carried by said carrier body and moveable laterally with respect thereto to engage said keeper and latch said tool in placein said core drilling assembly, means for normally holding said latching member in retracted inactive position, and means for moving said latching member to projected latching position and holding it in such position during the taking of a core, said last means including a solid plunger connected to said latching member and positioned in said zone of reduced diameter to substantially close the same when said tool is in normal operating position in said asembly and said latching member retracted and movable by fluid pressure downwardly out of said zone to project said latching member and open said passage for substantially free flow therethrough.

' JOHN E. HOFFOSS 

